To compare the efficacy, recurrence rate and safety of a single intravitreal injection of ranibizumab between type 1 prethreshold and threshold retinopathy of prematurity (ROP).

A retrospective cohort study was conducted.A total 100 eyes from 51 ROP patients in Xuzhou Municipal Hospital Affiliated to Xuzhou Medical University from January 2016 to December 2019 were enrolled.Retcam and indirect ophthalmoscope were used to confirm the diagnosis of 39 cases of type 1 prethreshold ROP (70 eyes) and 18 cases of threshold ROP (30 eyes). All the subjects were given a single intravitreal injection of ranibizumab (IVR) 0.25 mg/0.025 ml as the initial treatment within 24-36 hours after diagnosis.Events such as increased intraocular pressure, intraocular bleeding and endophthalmitis were observed and recorded 1 day after IVR.Retcam photography was used to check whether the fundus lesions was subsided 1 week after IVR.Regular follow-up was conducted once every 2-4 weeks until retinal vascularization.Systemic and ocular complications were recorded.The cure rate, the time of retinal vascularization and the recurrence rate of single IVR for type 1 prethreshold disease and threshold disease were compared.This study was approved by the Ethics Committee of Xuzhou Municipal Hospital Affiliated to Xuzhou Medical University.

After a single IVR, 86 of 100 eyes (86.00%) were cured, among which 60 of 70 type 1 prethreshold ROP eyes (85.71%) and 26 of 30 threshold ROP eyes (86.67%) were cured, with no significant difference between the two groups (χ²=0.09, P=0.65). No systemic adverse reactions were observed after a single IVR treatment.The final retinal vascularization time was (11.86±8.60) weeks in the type 1 prethreshold ROP group and (14.45±10.01) weeks in the threshold ROP group, with no statistically significant difference between the two groups (t=0.88, P=0.22). Recurrence of ROP appeared in 10 eyes after a single IVR, including 4 eyes (5.71%) in the type 1 prethreshold ROP group and 6 eyes (20.00%) in the threshold ROP group, the recurrent rate was significantly different between the two groups (χ²=4.76, P=0.03). Six recurrent eyes were treated with IVR for the second time, and 4 recurrent eyes were treated with laser photocoagulation.Five eyes presented with preretinal hemorrhage after IVR treatment, and were recovered without intervention.

The treatment of type 1 prethreshold ROP and threshold ROP with single IVR in vitreous cavity is safe and effective.The recurrence rate of threshold ROP is higher than type 1 prethreshold ROP.Retreatment can significantly improve the cure rate.

Retinopathy of prematurity; Ranibizumab; Intravitreal injection; Therapeutic effect; Safety